Master-pack

A Master-pack is a Jiralhanae organization far above the level of pack.[1] Incorporating a large number of smaller Packs, and likely organized under Alpha Tribes, it is likely that Master Packs are more like a political body than an actual military organization, with Packs serving as the military branches.
It is also possible that Master-Packs are as to Packs much like divisions are to companies.

Prior to the Jiralhanae's discovery by the Covenant, rival Master Packs had waged widespread mechanized warfare against each other across the surface of Doisac, causing such destruction that it reduced their species to a pre-industrial state.